Agilent Technologies has launched a simplified method for detecting sulphonamide antibiotics in pork. The company claims that the method reliably measures sulphonamides at lower than half the European Union and Canadian regulatory limits of 100 parts per billion (ppb) in meat.
The method uses conventional equipment, entails minimal sample preparation and has a maximum injection cycle of only 10 minutes. These advantages make the method particularly useful for high-throughput laboratories that monitor the food supply for drug residues.
Sulphonamides are broad-spectrum antimicrobials used in humans and animals. Their presence in the food supply is closely regulated because low-level exposure to these drugs can create antibiotic-resistant strains of bacteria. Out of all the antimicrobials, sulphonamide-based feed additives have caused the greatest residue problem and have received the most attention in recent years.
Agilent scientists used their newly developed technique to extract samples with acidified methanol. They then centrifuged the samples, and diluted a portion of the extract with water. Analysis of the dilution was conducted by high-performance liquid chromatography/atmospheric pressure chemical ionization/mass spectrometry (LC/APCI/MS), using an Agilent 1100 Series LC/MS system. All compounds eluted in less than five minutes.
Positive findings were confirmed on the MS detector during the same run. The method provides a statistically derived detection limit of 10 to 25 ppb for samples analysed by water dilution.
Antibiotics and chemotherapeutics are widely used in swinefeeds, in both the EU and North America. Processors claim that they are effective in improving the rate and efficiency ofgrowth and in reducing mortality and morbidity associated withrespiratory and intestinal diseases in pigs.
Certain feed additives, such as sulphonamide, require a withdrawal period prior to slaughter in order to insure that residues do not occur in the carcass.
In the 1970s, it was discovered that a worrying percentage of hog carcasses had violative sulphonamide residues. In almost allcases, the sulphonamide found in the carcass tissues was sulphamethazine. These findings initiated a raft of legislation on both sides of the Atlantic and increased levels of scrutiny.